Compass-drawn motifs are very common finds as graffiti and range in size from tiny – less than 2cm across, to nearly 1m (Norfolk). It has often been assumed that these designs were created by the stonemasons who built the church, either in teaching their apprentices the basics of geometry, or for other technical purposes.
It is now thought likely though that only a few were the work of masons, including the more complex and skilfully executed examples, and that the vast majority were created by other people, as ritual protection marks.
Although we use the term ‘compass-drawn’, actual compasses are rare finds in the archaeological record and their ownership is likely to have been restricted to craftsmen who used them in their work. It is uncertain what tools (quite possibly a variety) were used by other people for making these marks, but they may have included the more commonly carried shears or knives.
Among the many Devon examples, it is interesting that quite a few are imperfect circles, where the tool has perhaps slipped and the end of the line does not meet the starting point. There are also a number of rather irregular hand drawn hexafoils.